(19)
(11) EP 0 567 275 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
08.02.1995 Bulletin 1995/06

(43) Date of publication A2:
27.10.1993 Bulletin 1993/43

(21) Application number: 93302962.1

(22) Date of filing: 16.04.1993
(51) International Patent Classification (IPC)5: C23F 11/14, C02F 1/20, C07C 281/10, C07C 281/14, C07D 257/08
(84) Designated Contracting States:
DE GB IT

(30) Priority: 22.04.1992 US 872255

(71) Applicant: NALCO CHEMICAL COMPANY
Naperville Illinois 60563-1198 (US)

(72) Inventors:
  • Kelley, Douglas G.
    Naperville, Illinois 60540 (US)
  • Rogers, Deborah M.
    Naperville, Illinois 60540 (US)
  • Swiecinski, Frederick J.
    Algonquin, Illinois 60102 (US)

(74) Representative: Harrison, David Christopher et al
MEWBURN ELLIS York House 23 Kingsway
London WC2B 6HP
London WC2B 6HP (GB)


(56) References cited: : 
   
       


    (54) Carbohydrazones in the treatment of boiler water


    (57) The invention is directed to controlling corrosion in boiler systems and more particularly to treating boiler water with carbohydrazones to remove dissolved oxygen and to passivate metal surfaces. Carbohydrazones of the formulae


    or


    are claimed per se.





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